Modern buildings are generally required to satisfy stringent and evolving energy efficiency and insulation standards. For example, jurisdictions throughout North America are imposing building requirements directed to insulation values. For example, the ASHRAE 90.1 2010 Requirements for British Columbia, as per the BC Building Code. To meet the requirements of ASHRAE 90.1 2010 in British Columbia, the wall assembly must satisfy three criteria: an overall U-factor of not more than 0.064 BTU/(hr-ft2-oF); a minimum level of insulation equivalent to R13 (conventionally satisfied by 6″ of glass-fibre batt insulation, or by nominal 4″ batt insulation plus 1½″ of semi-rigid mineral-wool insulation); and a minimum of R7.5 continuous insulation.